In the Wild

Sloths Can't Get Fat (And 5 Other Unusual Facts About Them)

While they may be known as one of nature's laziest animals, sloths are also host to some very unusual and perhaps surprising attributes.

1. They are the only 'green' mammals.

Sloth fur is long and coarse and, while it is not actually green, the slow movement and inactivity of sloths allows algae enough time to grow in the fur, giving it a greenish tint. The algae are harmless to the sloth and help to camouflage them in the tree tops.

2. Ever wonder why you've never seen an obese sloth?

Sloths have extremely slow digestion. This means that the food, and any fat they consume, is very well absorbed and broken down by the time it's excreted. Most animals have small fat deposits in various locations of the body. In sloths, however, fat deposits have only ever been found on the pads of their feet.

3. Sloth teeth are all cone-shaped.

As omnivores, we have both carnivorous teeth (incisors and canines) as well as herbivorous teeth (molars and premolars). The herbivorous three-toed sloth, however, has neither. They have no structural similarity to that of other animals.

4. Sloths are excellent swimmers.

Three-toed sloths may look unsuited for any environment besides the canopies, but they are actually excellent swimmers. Should you ever come across a swimming sloth, there is no need to rescue it. Sloths can swim three times faster than they can move on land, and can hold their breath for over 40 minutes. They often reach the water by simply dropping themselves off the branches above.

5. Sloths' bodies are composed of only 25 percent muscle.

When all you have to do is hang from your claws, there's little need for muscles. Dense muscles would only weigh them down. They have almost no use of their hind legs when on the ground, and they also cannot shiver when cold. This makes them very susceptible to the cold on cooler days in South and Central America.

6. Ancient sloths were the size of elephants.

The three-toed sloths we're familiar with grow to be around 3.5 to 4.5 kilograms (approx. 8 to 10 pounds) and about 45 centimeters (approx. 18 inches) in length. Their colossal ancestors went extinct around 10,000 years ago. More recognizable relatives of three-toed sloths today include anteaters and armadillos.